Pen



FIG. 1 is a front view of the pen showing my new design thereof;

FIG. 2 is a top view thereof;

FIG. 3 is a bottom view thereof;

FIG. 4 is a right view thereof;

FIG. 5 is a left view thereof; and,

FIG. 6 is a back view thereof. 

CLAIM The ornamental design for a pen, as shown. 